The invention relates to a cage rotor according to the preamble of claim 1, an electrical machine which includes the cage rotor and a bar for the cage rotor. The invention further relates to a method for manufacturing the cage rotor.
Such a cage rotor is known from WO 2012/041943 A2. In this patent measures are described for improving the quality of a squirrel cage rotor and of an asynchronous machine, in order to overcome or to reduce the problems arising in such devices. The patent describes that a cage rotor of an asynchronous machine has a bar in a rotor laminated core, wherein the bar is able to be tipped at a tipping point. The bar is advantageously able to be tipped such that its ends can be tipped towards an axis of the squirrel cage rotor. A gap to the bar is thus produced in the end area of the rotor laminated core, wherein the bar can bend in the direction of the gap. The gap thus makes possible a bending of the ends of the rotor bars towards the axis. This has the advantage that the bar can yield to a force which arises when, during the hardening of the melt, the short-circuiting ring contracts and exercises a force on the bar in the direction of the axis of the squirrel cage rotor. This counteracts the problem of the contact resistance between the short-circuiting ring and the bar increasing if the bar cannot follow the short-circuiting ring shrinking during the cooling-off process. The connection point between bar and short-circuiting ring is definitively responsible for the operating data of the squirrel cage rotor or of the electrical machine. An improvement therein automatically leads to better electrical data, especially the efficiency.
Because of efforts to reduce the energy consumption significantly it is of central importance to make a further technical contribution which, on its own, as an alternative or in combination with known measures, makes possible a highly-efficient electrical machine.